schmeky
Member
I am going to acetylene weld my own parts (i.e. 1911 barrels for example) when necessary. Which tip size is best for welding barrel hoods and lower lugs? I know they start in the -0- range and go up.
Acetylene Welding
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highorder
Member
I'd try a 2, and trade up if it didn't offer enough heat...
Are you welding over firebrick, in a vise, etc?
Are you welding over firebrick, in a vise, etc?
You need to be careful on what parts of a firearm you're going to be using an acetylene torch on. Anything case hardened, or heat treated may not be safe to put back into a firearm after being subjected to that level of heat.
Barrels being one of them, they're heat treated at the factory to maintain a very specific mix of flexibility and strength. You can solder on a barrel with no trouble, but using an acetylene torch is going to mess with the heat treat and property of the metal.
Even turning a barrel down on a lathe is going to work-harden a barrel and mess with metal properties you don't want messed with on a barrel.
Barrels being one of them, they're heat treated at the factory to maintain a very specific mix of flexibility and strength. You can solder on a barrel with no trouble, but using an acetylene torch is going to mess with the heat treat and property of the metal.
Even turning a barrel down on a lathe is going to work-harden a barrel and mess with metal properties you don't want messed with on a barrel.
Make sure you understand the use of a heat sink for critical parts like bolts and barrels, and also the use of a heat protection paste to keep from ruining the finish on blued parts.
There is a difference between welding on the old hay bailer and welding on firearms.
Jim
There is a difference between welding on the old hay bailer and welding on firearms.
Jim
Gas welding on any alloy steel is a bad idea unless you know exactly what you are dealing with and have been trained to do it properly. This is particularly true if it has been heat treated.
Years ago I was certified to weld alloy steel airframes both with gas and TIG. It is not a trivial process if you want a reliable result.
One other point to consider: you mentioned barrels, many parts these days, barrels in particular, but also frames and slides are made from "free machining" steel alloys. These steel alloys contain either lead or sulfur and are not considered to be weldable.
Years ago I was certified to weld alloy steel airframes both with gas and TIG. It is not a trivial process if you want a reliable result.
One other point to consider: you mentioned barrels, many parts these days, barrels in particular, but also frames and slides are made from "free machining" steel alloys. These steel alloys contain either lead or sulfur and are not considered to be weldable.
rcmodel
Member in memoriam
Before there were commercially available 1911 Match barrels, welding the hood and cam lugs of a GI barrel with a gas welder was the only game in town.
I have done a lot of GI barrels years ago with never a problem.
I agree that todays mystery metals used by current barrel makers are not the same thing as an old GI barrel.
But it will work fine if you don't have a barrel made of some exotic metal.
rc
I have done a lot of GI barrels years ago with never a problem.
I agree that todays mystery metals used by current barrel makers are not the same thing as an old GI barrel.
But it will work fine if you don't have a barrel made of some exotic metal.
rc
Old Guard Dog
Member
If you gas weld, I would recommend a 3 1/2% nickel steel filler rod. TIG would be better. Remember, a lot of jobs can be done with a hard silver solder and not overheat the gun parts.
krs
Member
I used to use a small tip, Schmeky, like a "00" double ought, in the Victor scheme of things. Delicate little bead right around the edge of the hood and on the underside of the lugs just to add metal to work back down to a fit.
I had a gallon tin can with sand just for doing those, with the side cut out and the edges rolled inward. I filled the can with sand and wetted it thoroughly before each use then buried the whole barrel in my sand with only the hood or the lugs sticking out. Any one gallon tin can will work fine and they still sell laquer thinner in those some places.
It made for an easy way to position and handle the barrels as well as sinking the torch heat away from the chamber.
It was pretty much right out of an old NRA pamphlet titled "Accurizing the !911" that had been published in the 1960's, best I remember.
It's essentially the same thing rc is describing. Used to be the only way to get it done.
Seems like Jim Clark was the first to offer an aftermarket barrel but I might be wrong on that.
I had a gallon tin can with sand just for doing those, with the side cut out and the edges rolled inward. I filled the can with sand and wetted it thoroughly before each use then buried the whole barrel in my sand with only the hood or the lugs sticking out. Any one gallon tin can will work fine and they still sell laquer thinner in those some places.
It made for an easy way to position and handle the barrels as well as sinking the torch heat away from the chamber.
It was pretty much right out of an old NRA pamphlet titled "Accurizing the !911" that had been published in the 1960's, best I remember.
It's essentially the same thing rc is describing. Used to be the only way to get it done.
Seems like Jim Clark was the first to offer an aftermarket barrel but I might be wrong on that.
krs
Member
Schmeky,
If you can dig up a copy of Major George C. Nonte, Jr. "Handgun Competition" there's a chapter titled "Accurizing Autoloaders at Home" that describes the process and has a couple of photos showing the small amounts of added material needed. It was 1978, Winchester Press, ISBN 0-87691-253-6. Hardbound.
If you can dig up a copy of Major George C. Nonte, Jr. "Handgun Competition" there's a chapter titled "Accurizing Autoloaders at Home" that describes the process and has a couple of photos showing the small amounts of added material needed. It was 1978, Winchester Press, ISBN 0-87691-253-6. Hardbound.
rcmodel
Member in memoriam
Pistolsmithing by Nonte, and Modern Gunsmithing by MacFarland also cover welding up 1911 barrels.
Nonte says gas welding & Mac says arc welding but the process is the same.
rc
Nonte says gas welding & Mac says arc welding but the process is the same.
rc
schmeky
Member
Old Guard,
I have some 3 1/2% rods on the way from Brownell's. You mention the "hard silver solder", ironically, I am a former HVAC certifed technician and still have all my equipment, including some high silver content rods for heavy duty industrial applications. I sold and serviced industrial compressed air drying systems (including medical air systems) for 20 years. These high silver content rods are very difficult to work with, but I used these routinely and was very proficient with them. This was of course on non-ferrous copper.
I wonder if these would possibly work? Is there a specific flux for ferrous applications?
I'll check into the publications mentioned. I have an old plastic gas container I can use for the heat sink with sand . . . . . . just kidding.
I have some 3 1/2% rods on the way from Brownell's. You mention the "hard silver solder", ironically, I am a former HVAC certifed technician and still have all my equipment, including some high silver content rods for heavy duty industrial applications. I sold and serviced industrial compressed air drying systems (including medical air systems) for 20 years. These high silver content rods are very difficult to work with, but I used these routinely and was very proficient with them. This was of course on non-ferrous copper.
I wonder if these would possibly work? Is there a specific flux for ferrous applications?
I'll check into the publications mentioned. I have an old plastic gas container I can use for the heat sink with sand . . . . . . just kidding.
rcmodel
Member in memoriam
Silver Solder is not hard enough to take the beating it would get on the fitted cam lugs.
It might be O.K. on the barrel hood, but if it was me, I'd use the nickel steel rod.
rc
It might be O.K. on the barrel hood, but if it was me, I'd use the nickel steel rod.
rc
Jim Watson
Member
An article about Bob Day said he used acetylene and old magazine springs to weld up barrel hoods and link lugs for refitting. There is more detail in the Gun Digest Book of Pistolsmithing.
Assuming that the barrel is made out of 41xx alloy:
No flux is needed or wanted. The only time you'll use flux on 41xx is as a backup flux on a but joint, and if you weld the backside clean off all the flux before you weld it.
If you choose a 41xx filler material you will have to anneal, heat treat and temper the part again (or some combination of the 3). If you want to weld and go you will want to use an appropriate mild steel filler, something like ER70S6. Both pre and post-heating is important with either filler. I have no clue what the 3 1/2% Brownells rod is other than the nickle so your guess is as good as mine.
A gas grill can be used to both preheat and post-heat, heat is up to ~600F put the part in for 10 mins or so, take it out and weld it up with a neutral flame, adjust to a carbonizing flame and feather the weld then put the part back into the grill, leaving it on for ~30 mins and then turn it off and let it cool to ambient without removing the part. You can also just feather the part with a carbonizing flame to do the preheat and post-heat, just make the weld with a neutral flame. Another option is to bury the part in lime as an insulator after post-heating with a carbonizing flame, I've never done it but it's in just about every old school gunsmiting text.
TIG is very tricky to weld 41xx because the low Heat Affected Zone and the argon post flow can cool the weld too fast and make a brittle weld. When you have a low HAZ the rest of the part will act like a heat sink to the weld zone and draws the heat away from the weld while the argon post flow acts like an air quench.
What torch do you have (make and model)? Unless you have something like a meco midget or a smith airline (both are great torches for smaller work, the meco being smaller and more specialized and the Airline being a wonderful smallish general purpose torch) you'll probably want the smallest tip you can find.
FWIW I'm no welding expert so a grain or two of salt may be advisable.
No flux is needed or wanted. The only time you'll use flux on 41xx is as a backup flux on a but joint, and if you weld the backside clean off all the flux before you weld it.
If you choose a 41xx filler material you will have to anneal, heat treat and temper the part again (or some combination of the 3). If you want to weld and go you will want to use an appropriate mild steel filler, something like ER70S6. Both pre and post-heating is important with either filler. I have no clue what the 3 1/2% Brownells rod is other than the nickle so your guess is as good as mine.
A gas grill can be used to both preheat and post-heat, heat is up to ~600F put the part in for 10 mins or so, take it out and weld it up with a neutral flame, adjust to a carbonizing flame and feather the weld then put the part back into the grill, leaving it on for ~30 mins and then turn it off and let it cool to ambient without removing the part. You can also just feather the part with a carbonizing flame to do the preheat and post-heat, just make the weld with a neutral flame. Another option is to bury the part in lime as an insulator after post-heating with a carbonizing flame, I've never done it but it's in just about every old school gunsmiting text.
TIG is very tricky to weld 41xx because the low Heat Affected Zone and the argon post flow can cool the weld too fast and make a brittle weld. When you have a low HAZ the rest of the part will act like a heat sink to the weld zone and draws the heat away from the weld while the argon post flow acts like an air quench.
What torch do you have (make and model)? Unless you have something like a meco midget or a smith airline (both are great torches for smaller work, the meco being smaller and more specialized and the Airline being a wonderful smallish general purpose torch) you'll probably want the smallest tip you can find.
FWIW I'm no welding expert so a grain or two of salt may be advisable.
At the risk of being redundant. One of the most common barrel steels these days is 41L40. The "L" stands for lead. It contains lead to aid in high speed CNC/carbide tool machining. It is not considered a weldable alloy. Modern SS barrel steels also contain "free machining" alloying additives that tend to make them weld poorly.
Usually the welds end up with porosity or cracks which may not show up right away. You need to know for sure what alloy you are working with before you try to weld it particularly where safety is involved.
In addition: welding does more than creating a heat affected zone. The area adjacent and into the weld also has varying alloy content. Selection of the correct filler metal helps to adjust for these changes. You can't properly weld a modern alloy steel with "just anything". Successful post weld heat treating also cannot be done by "eyeball"; it has to be done under correct controls usually in a fairly narrow range.
Usually the welds end up with porosity or cracks which may not show up right away. You need to know for sure what alloy you are working with before you try to weld it particularly where safety is involved.
In addition: welding does more than creating a heat affected zone. The area adjacent and into the weld also has varying alloy content. Selection of the correct filler metal helps to adjust for these changes. You can't properly weld a modern alloy steel with "just anything". Successful post weld heat treating also cannot be done by "eyeball"; it has to be done under correct controls usually in a fairly narrow range.
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krs
Member
Mechanic's wire worked fine - it's mild steel wire. Your basic GI barrel though, nothing in a modern alloy.
Old Guard Dog
Member
Schmeky,
Brownells has a low temp (475 deg) High Force 44 silver solder with #4 Comet Flux, and a higher temp (650 deg) Hi Temp High Force 33 with Copper Bond flux. The low temp claims 14,000 to 28,000 psi strength and the Hi Temp claims 38,000 psi. I haven't used the hi temp, but the other one works great on stuff like a loose post on a ventilated shotgun rib. I also coat any bluing next to the joint with a regular pencil to keep the solder from creeping. I hear the hi temp works on stainless steel also. I have some other silver solder that works on SS, but I don't remember where I got it, or how strong it is.
Brownells has a low temp (475 deg) High Force 44 silver solder with #4 Comet Flux, and a higher temp (650 deg) Hi Temp High Force 33 with Copper Bond flux. The low temp claims 14,000 to 28,000 psi strength and the Hi Temp claims 38,000 psi. I haven't used the hi temp, but the other one works great on stuff like a loose post on a ventilated shotgun rib. I also coat any bluing next to the joint with a regular pencil to keep the solder from creeping. I hear the hi temp works on stainless steel also. I have some other silver solder that works on SS, but I don't remember where I got it, or how strong it is.
Common welding techniques could be expected to work on GI era barrels they were medium carbon steel so far as I know.
Just for reference, 41L40 heat treated into the common hardness range for a barrel (Rc40 or so) has a tensile strength of 120,000-180,000psi. (I didn't look it up - just from memory. We used to make parts from it.)
Just for reference, 41L40 heat treated into the common hardness range for a barrel (Rc40 or so) has a tensile strength of 120,000-180,000psi. (I didn't look it up - just from memory. We used to make parts from it.)
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Any 4140 material has to be post heated to a temp of 600 degree F before you even start to weld, whether it is done by oxy. and acet. or arc welding, tig or mig welding. After it is all said and done you then have to hold a post heat of 600 degrees from 1 - 3 hours, then cool as slow as possible. Peferrably covered in what we use- floor dry, which will keep the temp in for days.
I have been welding for over 34 years and this is what we do at the mine I work in.
I have been welding for over 34 years and this is what we do at the mine I work in.
rwsmuin:
I think you mean "pre heated"
Did you EVER weld 41L40 as opposed to 4140?
The pre heat is to avoid initial stress cracking in the "heat affected zone". The post welding cool off is to avoid air quenching and undesirable hardening. It sounds like you were welding very heavy sections for such a long post cooling time.
I think you mean "pre heated"
Did you EVER weld 41L40 as opposed to 4140?
The pre heat is to avoid initial stress cracking in the "heat affected zone". The post welding cool off is to avoid air quenching and undesirable hardening. It sounds like you were welding very heavy sections for such a long post cooling time.
I just have to ask, how do air frames that are welded 4130 tubing get their welds post heated? I know for a fact it gets done with a gas torch and we are talking about air frames. If you want a very good example of this from an authoritative source read page 833 of ASM Metal Handbook #6 on welding. For those that don't have this handbook:
1330 is a HTLA steel that is not that different than welding 4140. Notice that no post heating was prescribed, just gas welded it. Also notice the local stress relief that worked but was too labor intensive was just a man who knew what he was doing with a gas torch.
I have never heard of anybody using 41L40 for a barrel, but I do know that some use a sulfurized 41xx alloy, there is even a military spec for a sulfurized 4150 barrel steel. Regardless of which free machining material is used, solidification cracking is a huge issue. If this is the case pass. Solidification cracking is most defiantly viewable though.
RC 40 is incredibly hard for a barrel, for an example Crucible delivers their barrel spec 416R at RC 28-32. They have a 32/36 and a 24/28 but the 28/32 is their most popular.
Les Baer used to advertise their barrels at Rc38-40.
Look here under Specs: http://www.brownells.com/aspx/NS/store/ProductDetail.aspx?p=12689&title=1911 AUTO .355
I know this is a special barrel it is just the first one I found at Brownell with a hardness spec.
I agree with you re solidification cracking. In my experience there can also be cracking adjacent to the weld even if the weld appears to be sound but it may not appear until later as the stresses age out.
Aircraft chrome moly steel is not "free machining". When I was taught gas airframe welding the technique was to gradually preheat the area to be welded just short of "red". after welding the torch was played over the are and gradually withdrawn to allow slow cooling. It left the welded area basically annealed which was considered better than hard and brittle.
The post weld heat treating I was referring to was to return the part to its original properties.
Look here under Specs: http://www.brownells.com/aspx/NS/store/ProductDetail.aspx?p=12689&title=1911 AUTO .355
I know this is a special barrel it is just the first one I found at Brownell with a hardness spec.
I agree with you re solidification cracking. In my experience there can also be cracking adjacent to the weld even if the weld appears to be sound but it may not appear until later as the stresses age out.
Aircraft chrome moly steel is not "free machining". When I was taught gas airframe welding the technique was to gradually preheat the area to be welded just short of "red". after welding the torch was played over the are and gradually withdrawn to allow slow cooling. It left the welded area basically annealed which was considered better than hard and brittle.
The post weld heat treating I was referring to was to return the part to its original properties.
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